Countless Americans face vision loss issues due to cancer, degenerative eye diseases, diabetes and various other dangerous health problems. But one group of researchers decided to try to combat this serious issue. They came up with a groundbreaking theory: why not regrow a person’s cornea?
The researchers used stem cells to re-grow human corneal tissue. This new technical ability has the potential to cure blindness. Also noteworthy is the fact that this is the first time scientists have successfully created tissue utilizing adult-derived human stem cells.
Who conducted the study?
Fox explains, “In a new study published in the journal Nature, researchers from Massachusetts Eye and Ear Institute, Boston Children’s Hospital, Brigham and Women’s Hospital and the VA Boston Healthcare System detailed their groundbreaking research. According to the paper, the key to the study’s success revolves around a molecule known as ABCB5, which serves as a biomarker for previously elusive limbal stem cells. ”
The process is extremely complicated.
How did they come up with it? “Residing in the eye’s limbus – the border of the cornea and the whites of the eye – the limbal stem cells are responsible for maintaining and recreating corneal tissue. Because of their regenerative ability, scientists have long hoped to harness these stem cells for regrowing human tissue in those with blindness due to corneal injury or disease. Frank’s lab originally discovered the crucial ABCB5 molecule over 10 years ago, finding that it was present in skin and intestine precursor cells. But more recently, his team revealed that ABCB5 was also an important component of the eye’s limbal stem cells, preventing them from undergoing apoptosis – or cell death,” according to Fox.
The BBC also commented on the study by elaborating on why it was so important.
The BBC wrote, “Writing in the journal Nature, they say this method may one day help restore the sight of victims of burns and chemical injuries. Limbal stem cells (LSC) are crucial for healthy eyesight - these cells work to maintain, repair and completely renew our corneas every few weeks. Without them the cornea - the transparent outermost layer of the eye - would become cloudy and our vision disrupted. A deficiency of these cells due to disease or damage through injury to the eye are among the commonest reasons behind blindness worldwide. But the cells have so far been extremely difficult to identify, buried in a matrix of other structures in the limbal part of the eye - the junction between the cornea and the white of the eye (the sclera).”
Dr. Frank, the lead researcher (from Boston Children’s Hospital), said, “[The corneal tissue] – this is a tissue that has inherent turnover capacity; the cells are being shed and being replaced continuously. This capacity to restore is produced by the limbal stem cell population, and while it’s known that such cells exist, the identity and their exact molecular markers…have not been known. We showed that this capacity to regrow tissue was only located within the ABCB5-posivite graft. When we grafted in the same setup the ABCB5-negative cells, these cells were unable to do that.”
How does the graft work? “Using the corneal tissue from deceased human donors, the researchers were able to locate the limbal stem cells using antibodies that bind to ABCB5. Once they identified the stem cells, they extracted them from the donor tissue and transplanted them into mice whose limbal stem cells had been removed. As expected, fully normal human-derived corneal tissue was generated in the mice – allowing them to see once again. Most importantly, the process only worked when the limbal stem cells contained the critical ABCB5 molecule,” according to Fox.
The BBC explains, “Though ABCB5 has been known about for some time in other parts of the body, this is the first time it has been spotted on LSCs, helping to single out these elusive cells. Researchers have been able to tag these cells with fluorescent molecular flags. In their study, the scientists used this tagging technique to instantly identify a pool of LSCs on donated human corneas.”
In a nutshell, the researchers experimented with the technique by using mice. Luckily they had cells from donors of science to use to test their theory. In the final stages they transferred the stem cells to the mice, and the mice developed full functioning corneas. The most incredible aspect of these cells is that they have the remarkable ability to self-regenerate.
What does this mean for those suffering from blindness? Fox reports, “Since the loss of corneal tissue is one of the leading causes of blindness, the researchers hope this process will serve as a way to reverse any damage to the cornea, using unadulterated stem cells. Past studies have attempted to help the cornea regenerate by doing tissue or cell transplants, but the outcomes have not been consistent.”
What do other experts in the field say? The BBC reports that other experts are endorsing the study as well, “Harminder Dua, professor of ophthalmology at the University of Nottingham, who was not involved in this study, said: ‘This paper represents a very comprehensive and well conducted piece of work that takes use closer to the precise identification of stem cells. Applying this knowledge to a clinical setting could help improve the outcomes for patients who need corneal reconstruction’.”
Dr. Frank and his team are ecstatic about their findings. They did not expect the study to be so fruitful as it is extremely difficult to identify the ABCB5 marker. He explained what he hopes to do next and what his results prove,
“For the first step, we are really working towards an autologous graft in patients who are blind in one eye. And then for the second step, we would really work towards using donor derived cells to transplant in a similar manner that may require immune suppression – but it may not. We are glad to move this area forward, since [this marker] has really been the one thing missing in the field. But if you have a specific molecular marker to sort these stem cells out and arrive at a pure cell product for transplantation, that is huge.”
The study gives hope to the millions of Americans will serious vision problems. It is unclear how long it will take to actually start performing this procedure on humans but Dr. Frank and his team are saying the sooner the better. They hope to have it out by next year if not sooner.